1. Field of the Invention
The invention pertains to a gas spring including a bottom part, a cover, a rolling bellows fixed between the bottom part and the cover to form a gas filled spring space, and a sensor for determining the stroke position.
2. Description of the Related Art
A gas spring in combination with a vibration damper is known from ATZ 2002, Special Edition Audi A8, p. 86 ff. The gas spring comprises a cover, which is attached to the vehicle body and which is connected to the top end of a rolling bellows. A bottom end of the bellows is clamped to a rolldown tube. As can be derived from the report, a comparatively thin-walled bellows is used to minimize the stiffening of the gas spring under high-frequency excitation, A thin-walled bellows, however, is more sensitive to impacts by stones, so that a protective metal sleeve is used, which is also connected to the cover of the gas spring. The gas spring is part of a level control system, in which the level signal is determined by the use of a linkage inside the vehicle axle. The linkage is unavoidably exposed to dirt from the road and must be adjusted carefully to prevent the level from being set incorrectly.
U.S. Pat. No. 5,009,401 discloses a gas spring with a rigid cover, to which a tubular body is connected, which forms part of the spring space of the gas spring. Connected in turn to the tubular body is a rolling bellows, which is also clamped to a rolldown tube. A can-like part is also attached to the tubular body and has the function of supporting and protecting the rolling bellows. A height sensor is mounted in the rigid tubular body and is therefore located in a stationary position with respect to the piston rod; it can therefore be assumed that this is a pressure sensor. Because of its asymmetric profile, the tubular body is a comparatively expensive component.